If you had to pick...
 

2 12" KICKER 300wrms a piece compvr's in a ported 4 cubic foot box for 225$

or

1 10w6v1 500wrms in a sealed box for 165$

both used obviously..

either will be pushed by a clarion apx640.2 590wrms bridged so I think either setup would be ideal since both are dvc's anyways

kicker all the way.

The JL would have to be a dual 2ohm version to work properly with your amp. In any case, the kicker box wil be much louder than the JL, and assuming the box is designed right it should sound better to boot....

HTH

Kickers kicks JL in the mouth big time

Neither, I base this on the fact that a sub is the single most abused part of a stereo system. People in general (save for some people) like to dump abused subs to people under the premise that it works fine, then the issues start and you bought it "as is". Buy it used, buy it again when it dies a horrible death. Buy new and get a warranty and get looked after if it does have an issue.

I second that,i'll never buy another "used " sub, i did recently that was no good, the guy i got it from made good on the deal but it was still a hassle and i did wind up buying a new sub anyways.

I agree, i see alot of people selling stuff on here, and i don't mean anything negative but your asking for trouble buying used speakers.
I just bought kickers online, i can give you my old pioneers if you want? They work 'fine', but i wouldn't sell them to my son in law...